In the art of feeding documents, it is known to use interference separation in a feeder including separator wheels rotating in conjunction with a fixed stone for the purpose of feeding documents seriatim from a stack. In known inserters, the driving mechanism for such feeders generally has been a friction drive situated on the outside of the paper path of the inserter. Typically, the friction drives are operatively connected to and driven by the main drive assemblies of the inserter, and are controlled through the use of various clutch mechanisms. An example of such a feeder is described in U.S. Pat. No. 2,762,623 issued Sept. 11, 1956 to Uthenwoldt, et al. and assigned to the assignee of the present invention. Generally, the gear and clutch arrangement for such friction drives comprises a substantial number of parts. Over time, normal wear and tear on the friction drives parts causes them to exceed required tolerances for the operation of the machine which then requires service replacement of the worn parts. Furthermore, because such friction drives are located outside the paper path, the inserter size or "footprint" must include the additional area to house the cluster of shafts, clutches and gears which comprise the friction drives.
The insert feeder must also accommodate offset feeding adjustments as described, for example, in U.S. Pat. No. 4,501,417, issued Feb. 26, 1985 to Foster, et al. and assigned to the assignee of the present invention, U.S. Pat. No. 4,501,417 also describes apparatus to adjust the bite between the separator wheels and the stone. The method of adjustment taught by Foster, et al. comprises adjusting the separator stone and shield relative to a stationary separator wheel. Generally, a shield between in stone and the separator wheel is also adjusted to limit the amount of stone exposed to the separator wheels. Although the adjustments to the stone and shield work satisfactorily, several trial and error adjustments to the stone and shield are necessary in setting up the feeder for each type of document being fed. Another type of adjustment, as described in U.S. Pat. No. 4,782,095, issued Mar. 1, 1988 to Irvine, et al and assigned to the assignee of the present invention, comprises adjusting the separator roller relative to a retarding roller. U.S. Pat. No. 4,582,313, also assigned to assignee of present invention, shows an adjustment of a separator roller relative to a separator stone. Although these adjustment devices work satisfactorily, each time a change is made with regard to the characteristics of the document being fed, the trial and error adjustment begins all over because there is no reference from one adjustment to the next.